I have hope that your Orpington could be a pullet still. I wish I had better pictures to compare it to my pullets, but I attached the best I had to work with. The picture of the cockerel is under 6 weeks, a bit closer to five and the rest of the pictures of the pullets range from about two days before 6 weeks and two days after. I would expect yours to have a bit more red if he were a cockerel. I do acknowledge that every bird is different, especially different lines, but I think pullet or slow to mature cockerel. (Hoping pullet for you!). Your Ameraucana looks like a pullet. Definitely update pictures, it could go either way